I bought the TCL SOCL300 for around Rs. 400 ($5) from Amazon India.
The earpiece is super tiny and it sounded very weird on first listen with stock M-size tips. Everything seemed to be imaging to the right. I thought it had a channel imbalance so I measured them and it turned out to have great channel matching. Turns out it was a seal issue and going up to the stock L-size tips solved it.
These measurements are made on my DIY IEM measurement rig and are not accurate, and don’t necessarily represent what you might hear, especially before 60 Hz (huge sub-base roll-off) and after 10 kHz (and maybe even after 3 kHz as my ER2XR graph is very different compared to Crinacle’s post that). You can use it just to get a comparative idea, hence the comparison with ER2XR to give you a point of reference. Improving the rig is an ongoing process.
Here is Crinacle’s ER2XR graph for reference
It looks like final went with the mids to bass rise like in the E series and the highs of the A8000 on A4000.